Chemical Profile and Antifungal Activity of Leaf Extract of Tabernaemontana divaricata against Macrophomina phaseolina

Macrophomina phaseolina is a highly problematic fungus that causes diseases in hundreds of plant species. In order to search for an alternative to chemical fungicides for the control of this devastating pathogen, leaf extract of Tabernaemontana divaricata was assessed for the control of M. phaseolina. Five concentrations of leaf extract in methanol viz. 1, 2, 3, 4 and 5% (w/v), were checked against M. phaseolina. All these concentrations significantly suppressed the fungal growth resulting in 34–74% decreased biomass of M. phaseolina over control. GC-MS analysis of this extract showed the presence of 54 compounds. Squalene was the predominant compound with 24.11% peak area followed by vitamin E (8.96%). Other important compounds were hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester (6.21%), thiophene, tetrahydro-2-methyl- (5.68%), cyclopentanol (5.61%), neophytadiene (6.25%), 1-tert-butoxypropan-2-yl 2-methylbutanoate (6.03%), ibogamine-18-carboxylic acid, 12-methoxy-, methyl ester (2.95%), phytol (2.26%), and n-hexadecanoic acid (2.20%). Some of these major compounds might be responsible for antifungal property of methanolic leaf extract of T. divaricata against M. phaseolina.